std::basic_iostream(3) C++ Standard Libary std::basic_iostream(3) NAME std::basic_iostream - std::basic_iostream Synopsis Defined in header <istream> template< class CharT, class Traits = std::char_traits<CharT> > class basic_iostream : public basic_istream<CharT, Traits>, public basic_ostream<CharT, Traits> The class template basic_iostream provides support for high level in- put/output operations on streams. The supported operations include sequential read- ing or writing and formatting. This functionality is implemented over the in- terface provided by the std::basic_streambuf class. It is accessed through std::basic_ios class. std-basic iostream-inheritance.svg Inheritance diagram Several typedefs for common character types are provided: Defined in header <istream> Type Definition std::iostream std::basic_iostream<char> std::wiostream std::basic_iostream<wchar_t> Member types Member type Definition char_type CharT traits_type Traits; the program is ill-formed if Traits::char_type is not CharT. int_type Traits::int_type pos_type Traits::pos_type off_type Traits::off_type Member functions constructor constructs the object (public member function) destructor destructs the object [virtual] (virtual public member function) Protected member functions operator= move-assigns another basic_iostream (C++11) (protected member function) swap exchanges the state with another basic_iostream (C++11) (public member function) Inherited from std::basic_istream Member functions Formatted input operator>> extracts formatted data (public member function of std::basic_istream<CharT,Traits>) Unformatted input get extracts characters (public member function of std::basic_istream<CharT,Traits>) peek reads the next character without extracting it (public member function of std::basic_istream<CharT,Traits>) unget unextracts a character (public member function of std::basic_istream<CharT,Traits>) putback puts a character into input stream (public member function of std::basic_istream<CharT,Traits>) getline extracts characters until the given character is found (public member function of std::basic_istream<CharT,Traits>) ignore extracts and discards characters until the given character is found (public member function of std::basic_istream<CharT,Traits>) read extracts blocks of characters (public member function of std::basic_istream<CharT,Traits>) readsome extracts already available blocks of characters (public member function of std::basic_istream<CharT,Traits>) returns number of characters extracted by last unformatted input gcount operation (public member function of std::basic_istream<CharT,Traits>) Positioning tellg returns the input position indicator (public member function of std::basic_istream<CharT,Traits>) seekg sets the input position indicator (public member function of std::basic_istream<CharT,Traits>) Miscellaneous sync synchronizes with the underlying storage device (public member function of std::basic_istream<CharT,Traits>) Member classes sentry implements basic logic for preparation of the stream for input operations (public member class of std::basic_istream<CharT,Traits>) Inherited from std::basic_ostream Member functions Formatted output operator<< inserts formatted data (public member function of std::basic_ostream<CharT,Traits>) Unformatted output put inserts a character (public member function of std::basic_ostream<CharT,Traits>) write inserts blocks of characters (public member function of std::basic_ostream<CharT,Traits>) Positioning tellp returns the output position indicator (public member function of std::basic_ostream<CharT,Traits>) seekp sets the output position indicator (public member function of std::basic_ostream<CharT,Traits>) Miscellaneous flush synchronizes with the underlying storage device (public member function of std::basic_ostream<CharT,Traits>) Member classes sentry implements basic logic for preparation of the stream for output operations (public member class of std::basic_ostream<CharT,Traits>) Inherited from std::basic_ios Member types Member type Definition char_type CharT traits_type Traits int_type Traits::int_type pos_type Traits::pos_type off_type Traits::off_type Member functions State functions good checks if no error has occurred i.e. I/O operations are available (public member function of std::basic_ios<CharT,Traits>) eof checks if end-of-file has been reached (public member function of std::basic_ios<CharT,Traits>) fail checks if an error has occurred (public member function of std::basic_ios<CharT,Traits>) bad checks if a non-recoverable error has occurred (public member function of std::basic_ios<CharT,Traits>) operator! checks if an error has occurred (synonym of fail()) (public member function of std::basic_ios<CharT,Traits>) operator bool checks if no error has occurred (synonym of !fail()) (public member function of std::basic_ios<CharT,Traits>) rdstate returns state flags (public member function of std::basic_ios<CharT,Traits>) setstate sets state flags (public member function of std::basic_ios<CharT,Traits>) clear modifies state flags (public member function of std::basic_ios<CharT,Traits>) Formatting copyfmt copies formatting information (public member function of std::basic_ios<CharT,Traits>) fill manages the fill character (public member function of std::basic_ios<CharT,Traits>) Miscellaneous exceptions manages exception mask (public member function of std::basic_ios<CharT,Traits>) imbue sets the locale (public member function of std::basic_ios<CharT,Traits>) rdbuf manages associated stream buffer (public member function of std::basic_ios<CharT,Traits>) tie manages tied stream (public member function of std::basic_ios<CharT,Traits>) narrow narrows characters (public member function of std::basic_ios<CharT,Traits>) widen widens characters (public member function of std::basic_ios<CharT,Traits>) Inherited from std::ios_base Member functions Formatting flags manages format flags (public member function of std::ios_base) setf sets specific format flag (public member function of std::ios_base) unsetf clears specific format flag (public member function of std::ios_base) precision manages decimal precision of floating point operations (public member function of std::ios_base) width manages field width (public member function of std::ios_base) Locales imbue sets locale (public member function of std::ios_base) getloc returns current locale (public member function of std::ios_base) Internal extensible array xalloc returns a program-wide unique integer that is safe to use as index [static] to pword() and iword() (public static member function of std::ios_base) resizes the private storage if necessary and access to the long iword element at the given index (public member function of std::ios_base) resizes the private storage if necessary and access to the void* pword element at the given index (public member function of std::ios_base) Miscellaneous register_callback registers event callback function (public member function of std::ios_base) sync_with_stdio sets whether C++ and C I/O libraries are interoperable [static] (public static member function of std::ios_base) Member classes failure stream exception (public member class of std::ios_base) Init initializes standard stream objects (public member class of std::ios_base) Member types and constants Type Explanation stream open mode type The following constants are also defined: Constant Explanation app seek to the end of stream before each write binary open in binary mode openmode in open for reading out open for writing trunc discard the contents of the stream when opening ate seek to the end of stream immediately after open noreplace (C++23) open in exclusive mode (typedef) formatting flags type The following constants are also defined: Constant Explanation dec use decimal base for integer I/O: see std::dec oct use octal base for integer I/O: see std::oct hex use hexadecimal base for integer I/O: see std::hex basefield dec | oct | hex. Useful for masking opera- tions left left adjustment (adds fill characters to the right): see std::left right right adjustment (adds fill characters to the left): see std::right internal internal adjustment (adds fill characters to the internal designated point): see std::internal adjustfield left | right | internal. Useful for masking operations generate floating point types using scien- tific notation, scientific or hex notation if combined with fixed: see std::scientific fmtflags generate floating point types using fixed no- tation, or fixed hex notation if combined with scientific: see std::fixed floatfield scientific | fixed. Useful for masking opera- tions boolalpha insert and extract bool type in alphanumeric format: see std::boolalpha generate a prefix indicating the numeric base for integer showbase output, require the currency indicator in monetary I/O: see std::showbase showpoint generate a decimal-point character uncondi- tionally for floating-point number output: see std::show- point showpos generate a + character for non-negative nu- meric output: see std::showpos skipws skip leading whitespace before certain input operations: see std::skipws unitbuf flush the output after each output operation: see std::unitbuf replace certain lowercase letters with their uppercase uppercase equivalents in certain output operations: see std::uppercase (typedef) state of the stream type The following constants are also defined: Constant Explanation iostate goodbit no error badbit irrecoverable stream error failbit input/output operation failed (formatting or ex- traction error) eofbit associated input sequence has reached end-of- file (typedef) seeking direction type The following constants are also defined: seekdir Constant Explanation beg the beginning of a stream end the ending of a stream cur the current position of stream position indica- tor (typedef) event specifies event type (enum) event_callback callback function type (typedef) Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Cor- rect behavior the member types char_type, traits_type, LWG 271 C++98 int_type, pos_type and off_type were not defined de- fine (std::basic_istream and std::basic_ostream both these types define these types, resulted in ambiguity) See also * Input/output manipulators http://cppreference.com 2024.06.10 std::basic_iostream(3)
NAME | Synopsis | Member types | Member functions | Protected member functions | Member functions | Formatted input | Unformatted input | Positioning | Miscellaneous | Member classes | Member functions | Formatted output | Unformatted output | Positioning | Miscellaneous | Member classes | Member types | Member functions | State functions | Formatting | Miscellaneous | Member functions | Formatting | Locales | Internal extensible array | Miscellaneous | Member classes | Member types and constants | See also
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